If you are using Adobe PDF Reader, there is one thing you must absolutely do if you care about security.

DISABLE ACROBAT JAVASCRIPT ON YOUR ADOBE READER!!

This is very important. Even though Adobe always patches security vulnerabilities in their product, sometimes the exploit comes first and your computer could be infected by some nasty virus targeting the exploit.

The JavaScript feature is rarely used anyway. You better disable it now:

Open Adobe Reader

On the menu bar, go to Edit – Preferences

Go to the JavaScript tab

Untick the “Enable Acrobat JavaScript” option

Click OK.

Alternatively, you can use other software to read PDF files, e.g. Foxit Reader.